kernel: nsh: Restore skb->{protocol,data,mac_header} for outer header in nsh_gso_segment().

In the Linux kernel, the following vulnerability has been resolved: nsh: Restore skb-protocol,data,macheader for outer header in nshgsosegment. syzbot triggered various splats see 0 and links by a crafted GSO packet of VIRTIONETHDRGSOUDP layering the following protocols: ETHP8021AD + ETHPNSH +...